Various orthodontic appliances to correct tooth alignment of patients have been devised. Examples of known fixed-type orthodontic appliances include holding arches and multi-brackets. Examples of known removable-type orthodontic appliances include expansion plates and aligners. On the other hand, in order to correct the entire tooth alignment and to correct bimaxillary protrusion, for example, face masks, headgears, etc. as extraoral anchorage appliances may be used. In recent years, a concept called skeletal anchorage has been introduced, and various experiments have been undertaken to achieve highly predictable orthodontic treatment.